Scharping tested positive during the team’s bye week and went on the reserve list Oct. 28.
Contact tracing determined Mercilus and Cole were close contacts with outside linebacker Jacob Martin, who tested positive Wednesday. Martin remains on the COVID-19 reserve list.
Scharping could start at left guard in place of Senio Kelemete, who is in concussion protcol.
The Texans also announced two additions to their practice squad. Linebackers Kendall Futrell and Curtis Bolton signed after tryouts.
Houston cut receiver Devin Smith.